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View Full Version : stall and no high idle when cold and the car seems to be running rich. These 2 things related?



shreddr69
10-16-2011, 04:38 AM
My st165 with st185 motor with st165 intake manifold, distributor, ecu, sensors doesn't like to run when cold and once it warms up seems to be running rich. Could this be vacuum related or something else? Is there a cold idle adjustment and a fuel/ air ratio adjustment?

alltracman78
10-16-2011, 06:37 PM
You may have a bad coolant temp sensor.
Or the wiring may be bad.
If you used your 165 harness it's more likely you have a brittle, damaged wire that has been stressed to the point of breaking.

It's also possible your frankenstien mix may be causing the running rich, but it shouldn't cause the no high idle when cold.

shreddr69
10-16-2011, 07:08 PM
is there a simple way to find the wire if that's it? Also is there a way to adjust the air fuel ratio? Why do you think the frankensteining could cause an issue? I needed the Cali crap for smog so I'm kinda stuck with it. Also, there are no engine codes....

belanger33
10-16-2011, 11:39 PM
Coolant temp sensor X2

You may have a bad coolant temp sensor.
Or the wiring may be bad.
If you used your 165 harness it's more likely you have a brittle, damaged wire that has been stressed to the point of breaking.

It's also possible your frankenstien mix may be causing the running rich, but it shouldn't cause the no high idle when cold.

shreddr69
10-17-2011, 03:59 AM
How many coolant temp sensors are on this car, where are they and wouldn't it send a check engine code???

klapa
10-17-2011, 04:29 AM
Well I don't know what all "mix" you have - nor am I any expert by any means - but I know of at least two temp sensors on a 5th gen - ONE on the rad water neck to the upper rad hose - and one at the bottom of the rad itself for the fans control.

shreddr69
10-17-2011, 04:32 AM
could it have anything to do with the fact that my starter completely bypasses the the ECU and is wired to a James Bond switch on my dash?? I've been reading some other toyota forums and the cold start is controlled through power through the starter. Just thought I'd ask if there could be any relation.

alltracman78
10-17-2011, 04:46 PM
Cold start is unrelated to cold running.
The cold start system ONLY works while the starter is spinning.
The second you turn the key from start to run the cold start system turns off, so that's not your problem.

You're only going to get a MIL if a sensor completely stops working [no signal to the ECU]. The 165 and pre revision 185 have more primitive diagnostics. Your "tech" is probably used to OBDII cars. They WILL turn on the MIL if a sensor starts giving a bad signal [usually].
A sensor can still be "working", but not give the correct signal. So for example if your ECT [Engine Coolant Temp] sensor is telling your ECU the coolant is at 100*, while the coolant is actually at 50*, it's not going to turn the MIL on but it won't run right. A wire can also cause a wrong signal if it's corroded or partially broken.
It may also be your ISC valve [under the TB]. This is what the ECU uses to raise the idle when the engine is cold.

The best thing to do is check the ECT signal voltage at the ECU.
This will tell you what the ECU is seeing. The voltage will depend on what the temp is. The manual should explain it.


Well I don't know what all "mix" you have - nor am I any expert by any means - but I know of at least two temp sensors on a 5th gen - ONE on the rad water neck to the upper rad hose - and one at the bottom of the rad itself for the fans control.
The one at the bottom of the radiator isn't a sensor, it's a switch.
The second sensor is also in the coolant elbow, it's for the temp gauge in the dash. It's the single wire sensor.

shreddr69
10-20-2011, 02:32 AM
Tried a new coolant temp sensor and no difference so could you please explain to me how to check the engine coolant temp signal at the ECU and what type of voltage I'm looking for?

shreddr69
10-20-2011, 09:15 PM
I'm loosing my mind here. I ohm tested the idle controller, ok, I ohm tested the cold start injector next to another one that I know to be good and the test came out the same. THEN I tested the cold start injector timer and mine was a different ohm rating than the one I tested that I know to be good. I swapped them and still no difference. Same with the coolant temp sensor. Could it be the difference between the st165 and the st185 fuel rails? I'm using the st165 intake and the st185 fuel rail. And the st 165 fuel rail has the fuel pressure regulator and some other diapram built into it and the st185 fuel rail doesn't. Everything so far checks out fine. I have not tested the ECU because I don't know how so any ideas would be grrreatly appreciated and helpful. Thanks....

shreddr69
10-21-2011, 02:14 PM
HA HAHAHAHAHAHHAHHA, so I figured it out! I pulled the throttle body off to test everything right? Well, I figured I'd put the old gasket back in just to button it up over night until I got a new one. So at a glance the gasket looks correct but once I start trying to line it up, it didn't add up. The dowel holes don't align properly with the port to the ICV, no matter how I move or shift the gasket, no salami so I left it out, buttoned it up fired it up and it started perfectly! The gasket that my mechanic buddy put on was blocking off the ICV. Rock auto.com sent me the wrong gasket so if you order from them BE CAREFUL!! At a glance, it looks correct but not even close. I usually get those kind of gaskets from Toyota but I couldn't get there that week so I ordered it online. HUGE mistake. It won't happen again. So thank you to all who tried to help me I really appreciate it!!

Hookecho
10-21-2011, 04:21 PM
Good deal!

alltracman78
10-22-2011, 09:08 PM
Well done. :)

RedRkt01
10-28-2011, 08:14 PM
I had a similar problem at one time after replacing the TB gasket. When I went to undo the job and troubleshoot it I put the cheap autozone gasket next to the oem unit and sure enough they didn't match. Sorry I didn't see this thread until today :dunno:

shreddr69
11-01-2011, 02:52 AM
No, no, it's totally cool! I love this site! Everyone is so helpful! It's a beautiful thing. I was just beside myself when I figured it out. I was just SUCH A NICE FEELING!! @#$%!!!